Comparison of prevalence between self-reported erectile dysfunction and erectile dysfunction as defined by five-item International Index of Erectile Function in Taiwanese men older than 40 years.

Objectives: To conduct a cohort study in men older than 40 years in Taiwan to evaluate the prevalence of erectile dysfunction (ED) by self-report and the use of the abridged, five-item version of the International Index of Erectile Function (IIEF-5).

Methods: From July to August 2003, 990 Taiwanese men older than 40 years of age completed a telephone survey designed to assess ED prevalence and sexual functioning. ED was identified through respondent self-report and investigator assessment using the IIEF-5 instrument. Data were analyzed using the analysis of variance test, t test, and chi-square test, with Yates' correction or Fisher's method.

Results: The prevalence of self-reported ED was 13.1%, with 26.2% of this subgroup subsequently deemed to not have ED by IIEF-5 assessment. Among the subgroup of men self-reported to not have ED, 18.8% were found to have ED by IIEF-5 assessment. In total, 26.0% of respondents had ED by IIEF-5 assessment. The ED prevalence increased with age and a history of chronic illness. The frequency of sexual contact and sexual satisfaction were also reduced in the respondents with ED.

Conclusions: The prevalence of self-reported ED in Taiwanese men older than 40 years of age was 13.1% compared with 26.0% using the IIEF-5 assessment. Estimates of ED prevalence in the general population should not rely on self-reporting alone because it is likely to underestimate the true prevalence of ED.